The present invention relates generally to fluid distribution systems and more particulary to such systems having buried resilient fluid supply lines. Even more particularly, the present invention relates to a versatile and economical arrangement for selectively interrupting fluid flow in certain lines of such a fluid distribution system.
Perhaps the most commonly known and used fluid distribution systems are the buried conduit systems for supplying water and natural gas to businesses and residences and it is in this type environment in which the present invention will be described. Such systems typically employ main supply lines of relatively large cross-sectional area, feeding smaller service lines which run from the main lines to a particular consumer. It is frequently desirable to interrupt service to one or more consumers, for example, during line repair or maintenance, or during the construction and installation of additional service lines. Service interruptions are sometimes also occasioned by past due bills or simple non-use of the fluid by a particular consuming facility for an extended period of time.
One way commonly employed to interrupt fluid flow service is by the simple closing of a valve at the fluid source. This, of course, interrupts service to all consumers and is typically not desirable. Improved selectivity in the fluid interruption scheme is frequently achieved by providing so-called curb boxes which are access enclosures buried in the ground with their uppermost portion approximately flush or level with the surrounding terrain and having a removable cap through which access to an in-line shut-off valve may be obtained. A fluid distribution array with such periodic in-line valves is quite well suited to the normal use requirements but has the rather substantial drawback that a large number of relatively expensive valves must be built into the system at the selected locations so that a shut-off valve will be available when and where it is required, however, the vast majority of these valves are quite infrequently and indeed sometimes never actually used. Thus, while there is a relatively high investment in valving the distribution system, the utilization of this investment is quite poor.
It is also known in such distribution systems, particularly in the event of an emergency leak situation, to uncover the supply line and interrupt fluid flow therethrough by physically squeezing the line shut. Commercially available line squeezing devices are quite large, generally requiring two men for positioning and actuating the line squeezer, and frequently their use renders the line unsuitable for further use.
The use of plastic distribution lines, particularly in natural gas and water supply systems, has become fairly common in recent years, however, the schemes for selective service interruption remain about the same as described above. There is a need for an easily and quickly interruptible fluid distribution system having a low initial installation cost.